new isothermal titration calorimeter for investigations on very small samples: Theoretical and experimental studies

A new isothermal titration calorimeter with 78.5 μL volume capillary chambers has been developed. It is based on the theory of mixing reagents in a capillary chamber of a titration calorimeter and separation of the sensitive volume of chambers in a differential calorimeter. The evaluation of the efficiency of diffusion mixing is described by means of an oscillating dispensing needle. The calorimeter was tested by the reactions: Ba2+– 18-Crown-6 and Rnase-2’CMP. The main advantages of the new titration calorimeter are the use of very small amounts of reagents, the high accuracy of separating the sensitive volume of calorimetric chambers and the minimization of power input while mixing reagents in a horizontally located capillary chamber.